knocking sound
 

hey everybody... here it goes... i was doing a 3rd gear data log because i wanted to bounce the boost pressure off my old logs because i have been hunting down small boost leaks. i also was monitering my HPFP internals because im getting ready for the track. i am running cobbs stage 1+ injcai. anyway as the rpms are falling after the log i eased onto the throttle to maintain speed to do one more log and just about as soon as i touched the throttle i heard a rattling sound so i pulled over immidiatly and the sound is consistent with the RPMs. at idle its consitent and when i hit the throttle i hear it for a few seconds then it goes away. it comes back when i the rpms are falling... from what i am reading it sounds like the vvt or the timing chain. i will post a video and the log when i get home... i have the graveyard shift tonight. oh and when i started hearing the noise i checked the kr and there was 0 degrees of Kr and no cels... i got the car towed back to my house because the fear of ZZB has been instilled upon me lol. anyway thanks in advance for any insight and advice. also a video will be uploaded shortly... thanks again

-Taz

Belt tensioner and/or idler pulley.

i tried uploading the video from my phone but it said invalid file so im emailing it to my gov computer and ill try it from here... thanks for the help. ill read up on that

stupid knocking sound - YouTube

i think thats how you do it lol here is a short vid of it cold... a littl worried about letting it idle till warm to check the chain... also those revs were barely 2200rpm. thank you in advance

That sounds like a spun rod bearing. @Snotrocket;

yeah that sounds like a rod knock to me.

Thanks guys.... Is there any point in trying to diagnose this further? I have a friend with a trailer so I'm going to tow it to the stealorship when I get a chance because I don't have yine to rebuild te motor or throw parts at it to be optimistic about rebuilding.... Damn the car felt so strong just before this happened...

Yours does not sound like mine IMO, but there is a video of my fucked up belt tensioner.
http://www.mazdaspeedforums.org/foru...f-sound-74286/

alright after talking to my buddies and looking at parts it looks like i will be dropping the oilpan and trouble shooting further. if i have t rebuild i will be starting a build thread. thanks for the help. everybody it was greatly appreciated

Taz, that's a fucking spun bearing. You're fucked. You had the correct amount of oil inside the the oil pan, right? There should be flakes inside the oil. If the rods aren't fucked, I guess technically you can just drop the oil pan, take out the end caps for the connecting rod, push the rod up and replace the bearings. I'd inspect the crank though, hopefully it isn't fucked.

If it isn't I'd measure the clearances and buy new bearings, lube them up and install from there. It'd be a real pain in the dick if you're taking the motor out. I'm probably going to get groaned n shit because the proper way is to remove the motor and inspect everything. It'd be around $100 to replace the bearings and doing the work yourself

This sucks for you man sorry, when I heard you start your engine up my stomach got sick I have heard that sound b4 and it is rod knock. I am curious what where you running for motor oil? Have you been doing your oil changes your self? If not where have you been getting them done at?

Also get with your local nator I am sure they can help you out one way or another with this and limit out long you are with out a car.